X-ray spectroscopy: An experimental technique to measure charge state distribution during ion–solid interaction

• New method is proposed to determine charge state distribution using X-ray technique.
• Charge state distribution parameters are calculated and compared with various theoretical predictions.
• X-ray technique is found to be appropriate to segregate the charge state distribution in the bulk from the target surface.
• ETACHA predictions are found satisfactory in the energy range of ≥1.65 MeV/u.

Charge state distributions of 56Fe and 58Ni projectile ions passing through thin carbon foils have been studied in the energy range of 1.65–2.69 MeV/u using a novel method involving the X-ray spectroscopy technique. Interestingly the charge state distribution in the bulk shows Lorentzian behavior instead of usual Gaussian distribution. Further, different parameters of charge state distribution like mean charge state, distribution width and asymmetric parameter are determined and compared with the empirical calculations and ETACHA predictions. It is found that the X-ray measurement technique is appropriate to determine the mean charge state during the ion–solid interaction or in the bulk. Interestingly, empirical formalism predicts much lower mean charge states of the projectile ions compared to X-ray measurements which clearly indicate multi-electron capture from the target surface. The ETACHA predictions and experimental results are found to be comparable for the present energy regime.